For the past six years, Mr. Chen, a Taiwanese home-appliance salesman, has been living a double life. For one thing, Chen isn’t his real surname – he adopts the pseudonym Xiao Chen, or Little Chen, on weekends. For another, in his downtime he forgoes casual attire such as jeans and T-shirts, and instead dresses up as his favorite female cartoon character.

Like more than 120,000 people in Taiwan and millions around the world, Mr. Chen, 25, is a passionate fan of cosplay – a contraction of “costume” and “play” – a growing subculture that originated in Japan. Participants use elaborate makeup and clothes to role-play characters and objects from cartoons, comic books and videogames.

Jenny Hsu for The Wall Street Journal

Cosplay participants use makeup and costumes to role-play characters and objects from cartoons, comic books and videogames.

“I’m not ashamed of my hobby,” said Mr. Chen at a cosplay gathering at Taipei Main Station plaza this month, though he added that “my family would probably disown me if they ever found out.” Around six foot tall and bulky, he was sporting a blue maid costume inspired by the central character in “Magical Girl Madoka of the Magus,” his favorite Japanese anime series.

“I know there are many negative conceptions of cosplay, but for me, it’s a stress reliever,” he said. “Cosplay allows me to be the real me after a week of pretending to be the person that the society expects me to be.”

Another cosplayer at the event, a 17-year-old high school student who goes by the alias Penguin, said that dressing up like the wise man Ja’far from her favorite Japanese manga series “Magi – Labyrinth of Magic,” made her feel “powerful” – albeit only for few hours. Fearful of crowds and often labeled as a loner, the self-described introvert said she now has no problem striking poses for anyone who wants to take her picture.

“I finally don’t feel left out because I feel understood,” she said. “You can say I am defying tradition, but I think I am just part of the latest trend.”

According to Comic World Taiwan’s chief officer Cheng Wen-fu, cosplay was heavily frowned upon when it was first introduced in Taiwan two decades ago “because the public was too conservative to accept any nonconformist displays of self-expression.”

“The culture was demonized by the media [which said] that only sex fiends and social degenerates participate in cosplay,” he said. “I don’t deny that some cosplayers fit that bill, but they are definitely in the minority.”

“Just because a few baseball players rig some games,” he added, “doesn’t mean the sport itself is bad.”

Thanks to the prevalence of online games and comics, cosplay has grown into a world-wide phenomenon. In 2011, cosplayers in Europe from 23 countries gathered in London for the EuroCosplay Championships Final. In Asia, cosplay is booming in locations such as China, Hong Kong and South Korea.

Taiwan has its own unique cosplay style, inspired by the island’s traditional puppet shows. For many adults nowadays, Mr. Cheng said, characters from classical puppet shows were their childhood companions and heroes, and to transform into one of them “is a fantasy come true.”

Though puppet shows were once a fading art form, they have recently made a comeback thanks to cosplay. “Cosplay and Taiwanese puppet shows enjoy a symbiotic relationship,” said Mr. Cheng. “People’s fondness for the puppet shows helps de-stigmatize cosplay, and cosplay is restoking the popularity of the art form among the younger generation.”

Comic World Taiwan and other cosplay groups are capitalizing on that relationship on May 26 at the first Taiwan Super Cosplay Celebration and Competition in the southern county of Yunlin, considered the birthplace of classical Taiwanese puppet shows. The event is not only a gathering of cosplay enthusiasts around the island, but also a chance for local cosplayers to convince the visiting Japanese judges that Taiwan qualifies as a participant in next year’s World Cosplay Summit, an annual mega-event held in Nagoya, Japan, hailed as the Olympics of the cosplay world.

As for Mr. Chen, the outcome won’t change how he feels about cosplay. “I know people consider our hobby weird but that’s their choice,” he said. “For me, my choice is to cosplay for as long as I feel like it,” he added, swinging his hips confidently as he walked into a crowd of green-eyed ninjas, sword-wielding wizards and zombie brides, in a pair of bright red pumps.